Some agricultural devices have pressurized compartments, such as an agricultural planter. A planter is an agricultural farm implement typically towed behind a tractor that is used for planting crops in a field. The planter, air seeder or a grain drill lay the seed down in a predetermined precise manner along a series of parallel rows. The seeds that are planted are distributed through numerous row units that are generally spaced evenly along a portion of the planter. Planters vary greatly in size, from 2 rows even up through the 48-row John Deere DB120.
Historically, on smaller and older planters, a marker stick extends from the side of the planter to half the width of the planter. The marker stick has some element that drags in the soil causing a line to be drawn in the field so that the operator of the tractor knows hoe to position the tractor for the return trip across the field. On larger modern planters, a GPS navigation system as well as autopilot type steering is used to guide the planter across the field to maintain proper row spacing.
Older planters typically had a seed bin for each row, with each seed bin generally would have plates with a predetermined number of teeth with predetermined spacing depending on the type of seed to be sown and the desired spacing of the seeds in the soil. Modern planters generally have one or more large seed tanks with the seeds being distributed to each row unit. The row units perform the final task of seed metering and placement. The seed delivery process may rely on a hydraulically-driven fan to move the seed from the seed tanks to the row units. A flow control valve and gauge allows for the proper tank pressure setting based on seed type. Air from the fan pressurizes the seed tanks and delivers seed to the seed hoppers. Airflow enters the seed tanks through a nozzle in the manifold, which pressurizes the tank. The air then picks up seed and moves it out the other end of the nozzle into seed delivery hoses. These hoses route the seed toward the hopper. A small amount of seed is traveling in the delivery hoses only when needed. The hopper fills with seed until the delivery hose is covered. Once the opening is restricted, seed flow through the hose stops. Air flowing to the row unit travels into the hopper and out through a vent. As the seed is picked up by the meter and planted, the seed pool shrinks until the end of the delivery hose is uncovered. At that time, the airflow and seed delivery resume and the seed pool in the hopper is replenished.
It is important to maintain air pressure in the seed tank while planting is underway in order to maintain consistent planting. If the fill lid of the planter is opened the air pressure is lost and with it the ability to transfer the seeds therefrom.
What is needed in the art is a method and apparatus to transfer material in the form of seeds into a pressurized compartment while the machine is functioning without the loss of pressurized air in the compartment in an efficient economical manner.